class Rulers {
  constructor() {
    this.data = [];
  }

  create(Type, points) {
    const ruler = new Type(points);
    this.data.push(ruler);
    return ruler;
  }

  toString() {
    return this.data.map((ruler) => ruler.toString()).join('; ');
  }

  fromString(string) {
    this.data = [];

    const rulers = string.split('; ');
    for (const rulerString of rulers) {
      const [type, pointsString] = rulerString.split(': ');
      const points = pointsString.split(' ').map((el) => el.split(',').map((n) => +n));
      const Type = type === 'Ruler' ? Ruler : type === 'Opisometer' ? Opisometer : type === 'RouteOpisometer' ? RouteOpisometer : type === 'Planimeter' ? Planimeter : null;
      this.create(Type, points);
    }
  }

  draw() {
    this.data.forEach((ruler) => ruler.draw());
  }

  undraw() {
    this.data.forEach((ruler) => ruler.undraw());
  }

  remove(id) {
    if (id === undefined) return;

    const ruler = this.data.find((ruler) => ruler.id === id);
    ruler.undraw();
    const rulerIndex = this.data.indexOf(ruler);
    rulers.data.splice(rulerIndex, 1);
  }
}

class Measurer {
  constructor(points) {
    this.points = points;
    this.id = rulers.data.length;
  }

  toString() {
    return this.constructor.name + ': ' + this.points.join(' ');
  }

  getSize() {
    return rn((1 / scale ** 0.3) * 2, 2);
  }

  getDash() {
    return rn(30 / distanceScaleInput.value, 2);
  }

  drag() {
    const tr = parseTransform(this.getAttribute('transform'));
    const x = +tr[0] - d3.event.x,
      y = +tr[1] - d3.event.y;

    d3.event.on('drag', function () {
      const transform = `translate(${x + d3.event.x},${y + d3.event.y})`;
      this.setAttribute('transform', transform);
    });
  }

  addPoint(point) {
    const MIN_DIST = d3.event.sourceEvent.shiftKey ? 9 : 100;
    const prev = last(this.points);
    point = [point[0] | 0, point[1] | 0];
    const dist2 = (prev[0] - point[0]) ** 2 + (prev[1] - point[1]) ** 2;
    if (dist2 < MIN_DIST) return;
    this.points.push(point);
    this.updateCurve();
    this.updateLabel();
  }

  optimize() {
    const MIN_DIST2 = 900;
    const optimized = [];

    for (let i = 0, p1 = this.points[0]; i < this.points.length; i++) {
      const p2 = this.points[i];
      const dist2 = !i || i === this.points.length - 1 ? Infinity : (p2[0] - p1[0]) ** 2 + (p2[1] - p1[1]) ** 2;
      if (dist2 < MIN_DIST2) continue;
      optimized.push(p2);
      p1 = p2;
    }

    this.points = optimized;
    this.updateCurve();
    this.updateLabel();
  }

  undraw() {
    this.el?.remove();
  }
}

class Ruler extends Measurer {
  constructor(points) {
    super(points);
  }

  getPointsString() {
    return this.points.join(' ');
  }

  updatePoint(index, x, y) {
    this.points[index] = [x, y];
  }

  getPointId(x, y) {
    return this.points.findIndex((el) => el[0] == x && el[1] == y);
  }

  pushPoint(i) {
    const [x, y] = this.points[i];
    i ? this.points.push([x, y]) : this.points.unshift([x, y]);
  }

  draw() {
    if (this.el) this.el.selectAll('*').remove();
    const points = this.getPointsString();
    const size = this.getSize();
    const dash = this.getDash();

    const el = (this.el = ruler
      .append('g')
      .attr('class', 'ruler')
      .call(d3.drag().on('start', this.drag))
      .attr('font-size', 10 * size));
    el.append('polyline')
      .attr('points', points)
      .attr('class', 'white')
      .attr('stroke-width', size)
      .call(d3.drag().on('start', () => this.addControl(this)));
    el.append('polyline')
      .attr('points', points)
      .attr('class', 'gray')
      .attr('stroke-width', rn(size * 1.2, 2))
      .attr('stroke-dasharray', dash);
    el.append('g')
      .attr('class', 'rulerPoints')
      .attr('stroke-width', 0.5 * size)
      .attr('font-size', 2 * size);
    el.append('text')
      .attr('dx', '.35em')
      .attr('dy', '-.45em')
      .on('click', () => rulers.remove(this.id));
    this.drawPoints(el);
    this.updateLabel();
    return this;
  }

  drawPoints(el) {
    const g = el.select('.rulerPoints');
    g.selectAll('circle').remove();

    for (let i = 0; i < this.points.length; i++) {
      const [x, y] = this.points[i];
      this.drawPoint(g, x, y, i);
    }
  }

  drawPoint(el, x, y, i) {
    const context = this;
    el.append('circle')
      .attr('r', '1em')
      .attr('cx', x)
      .attr('cy', y)
      .attr('class', this.isEdge(i) ? 'edge' : 'control')
      .on('click', function () {
        context.removePoint(context, i);
      })
      .call(
        d3
          .drag()
          .clickDistance(3)
          .on('start', function () {
            context.dragControl(context, i);
          })
      );
  }

  isEdge(i) {
    return i === 0 || i === this.points.length - 1;
  }

  updateLabel() {
    const length = this.getLength();
    const text = rn(length * distanceScaleInput.value) + ' ' + distanceUnitInput.value;
    const [x, y] = last(this.points);
    this.el.select('text').attr('x', x).attr('y', y).text(text);
  }

  getLength() {
    let length = 0;
    for (let i = 0; i < this.points.length - 1; i++) {
      const [x1, y1] = this.points[i];
      const [x2, y2] = this.points[i + 1];
      length += Math.hypot(x1 - x2, y1 - y2);
    }
    return length;
  }

  dragControl(context, pointId) {
    let addPoint = context.isEdge(pointId) && d3.event.sourceEvent.ctrlKey;
    let circle = context.el.select(`circle:nth-child(${pointId + 1})`);
    const line = context.el.selectAll('polyline');

    let x0 = rn(d3.event.x, 1);
    let y0 = rn(d3.event.y, 1);
    let axis;

    d3.event.on('drag', function () {
      if (addPoint) {
        if (d3.event.dx < 0.1 && d3.event.dy < 0.1) return;
        context.pushPoint(pointId);
        context.drawPoints(context.el);
        if (pointId) pointId++;
        circle = context.el.select(`circle:nth-child(${pointId + 1})`);
        addPoint = false;
      }

      const shiftPressed = d3.event.sourceEvent.shiftKey;
      if (shiftPressed && !axis) axis = Math.abs(d3.event.dx) > Math.abs(d3.event.dy) ? 'x' : 'y';

      const x = axis === 'y' ? x0 : rn(d3.event.x, 1);
      const y = axis === 'x' ? y0 : rn(d3.event.y, 1);

      if (!shiftPressed) {
        axis = null;
        x0 = x;
        y0 = y;
      }

      context.updatePoint(pointId, x, y);
      line.attr('points', context.getPointsString());
      circle.attr('cx', x).attr('cy', y);
      context.updateLabel();
    });
  }

  addControl(context) {
    const x = rn(d3.event.x, 1);
    const y = rn(d3.event.y, 1);
    const pointId = getSegmentId(context.points, [x, y]);

    context.points.splice(pointId, 0, [x, y]);
    context.drawPoints(context.el);
    context.dragControl(context, pointId);
  }

  removePoint(context, pointId) {
    if (this.points.length < 3) return;
    this.points.splice(pointId, 1);
    context.draw();
  }
}

class Opisometer extends Measurer {
  constructor(points) {
    super(points);
  }

  draw() {
    if (this.el) this.el.selectAll('*').remove();
    const size = this.getSize();
    const dash = this.getDash();
    const context = this;

    const el = (this.el = ruler
      .append('g')
      .attr('class', 'opisometer')
      .call(d3.drag().on('start', this.drag))
      .attr('font-size', 10 * size));
    el.append('path').attr('class', 'white').attr('stroke-width', size);
    el.append('path').attr('class', 'gray').attr('stroke-width', size).attr('stroke-dasharray', dash);
    const rulerPoints = el
      .append('g')
      .attr('class', 'rulerPoints')
      .attr('stroke-width', 0.5 * size)
      .attr('font-size', 2 * size);
    rulerPoints
      .append('circle')
      .attr('r', '1em')
      .call(
        d3.drag().on('start', function () {
          context.dragControl(context, 0);
        })
      );
    rulerPoints
      .append('circle')
      .attr('r', '1em')
      .call(
        d3.drag().on('start', function () {
          context.dragControl(context, 1);
        })
      );
    el.append('text')
      .attr('dx', '.35em')
      .attr('dy', '-.45em')
      .on('click', () => rulers.remove(this.id));

    this.updateCurve();
    this.updateLabel();
    return this;
  }

  updateCurve() {
    lineGen.curve(d3.curveCatmullRom.alpha(0.5));
    const path = round(lineGen(this.points));
    this.el.selectAll('path').attr('d', path);

    const left = this.points[0];
    const right = last(this.points);
    this.el.select('.rulerPoints > circle:first-child').attr('cx', left[0]).attr('cy', left[1]);
    this.el.select('.rulerPoints > circle:last-child').attr('cx', right[0]).attr('cy', right[1]);
  }

  updateLabel() {
    const length = this.el.select('path').node().getTotalLength();
    const text = rn(length * distanceScaleInput.value) + ' ' + distanceUnitInput.value;
    const [x, y] = last(this.points);
    this.el.select('text').attr('x', x).attr('y', y).text(text);
  }

  dragControl(context, rigth) {
    const MIN_DIST = d3.event.sourceEvent.shiftKey ? 9 : 100;
    let prev = rigth ? last(context.points) : context.points[0];

    d3.event.on('drag', function () {
      const point = [d3.event.x | 0, d3.event.y | 0];

      const dist2 = (prev[0] - point[0]) ** 2 + (prev[1] - point[1]) ** 2;
      if (dist2 < MIN_DIST) return;

      rigth ? context.points.push(point) : context.points.unshift(point);
      prev = point;

      context.updateCurve();
      context.updateLabel();
    });

    d3.event.on('end', function () {
      if (!d3.event.sourceEvent.shiftKey) context.optimize();
    });
  }
}

class RouteOpisometer extends Measurer {
  constructor(points) {
    super(points);
    if (pack.cells) {
      this.cellStops = points.map((p) => findCell(p[0], p[1]));
    } else {
      this.cellStops = null;
    }
  }

  checkCellStops() {
    if (!this.cellStops) {
      this.cellStops = this.points.map((p) => findCell(p[0], p[1]));
    }
  }

  trackCell(cell, rigth) {
    this.checkCellStops();
    const cellStops = this.cellStops;
    const foundIndex = cellStops.indexOf(cell);
    if (rigth) {
      if (last(cellStops) === cell) {
        return;
      } else if (cellStops.length > 1 && foundIndex != -1) {
        cellStops.splice(foundIndex + 1);
        this.points.splice(foundIndex + 1);
      } else {
        cellStops.push(cell);
        this.points.push(this.getCellRouteCoord(cell));
      }
    } else {
      if (cellStops[0] === cell) {
        return;
      } else if (cellStops.length > 1 && foundIndex != -1) {
        cellStops.splice(0, foundIndex);
        this.points.splice(0, foundIndex);
      } else {
        cellStops.unshift(cell);
        this.points.unshift(this.getCellRouteCoord(cell));
      }
    }
    this.updateCurve();
    this.updateLabel();
  }

  getCellRouteCoord(c) {
    const cells = pack.cells;
    const burgs = pack.burgs;
    const b = cells.burg[c];
    const x = b ? burgs[b].x : cells.p[c][0];
    const y = b ? burgs[b].y : cells.p[c][1];
    return [x, y];
  }

  draw() {
    if (this.el) this.el.selectAll('*').remove();
    const size = this.getSize();
    const dash = this.getDash();
    const context = this;

    const el = (this.el = ruler
      .append('g')
      .attr('class', 'opisometer')
      .attr('font-size', 10 * size));
    el.append('path').attr('class', 'white').attr('stroke-width', size);
    el.append('path').attr('class', 'gray').attr('stroke-width', size).attr('stroke-dasharray', dash);
    const rulerPoints = el
      .append('g')
      .attr('class', 'rulerPoints')
      .attr('stroke-width', 0.5 * size)
      .attr('font-size', 2 * size);
    rulerPoints
      .append('circle')
      .attr('r', '1em')
      .call(
        d3.drag().on('start', function () {
          context.dragControl(context, 0);
        })
      );
    rulerPoints
      .append('circle')
      .attr('r', '1em')
      .call(
        d3.drag().on('start', function () {
          context.dragControl(context, 1);
        })
      );
    el.append('text')
      .attr('dx', '.35em')
      .attr('dy', '-.45em')
      .on('click', () => rulers.remove(this.id));

    this.updateCurve();
    this.updateLabel();
    return this;
  }

  updateCurve() {
    lineGen.curve(d3.curveCatmullRom.alpha(0.5));
    const path = round(lineGen(this.points));
    this.el.selectAll('path').attr('d', path);

    const left = this.points[0];
    const right = last(this.points);
    this.el.select('.rulerPoints > circle:first-child').attr('cx', left[0]).attr('cy', left[1]);
    this.el.select('.rulerPoints > circle:last-child').attr('cx', right[0]).attr('cy', right[1]);
  }

  updateLabel() {
    const length = this.el.select('path').node().getTotalLength();
    const text = rn(length * distanceScaleInput.value) + ' ' + distanceUnitInput.value;
    const [x, y] = last(this.points);
    this.el.select('text').attr('x', x).attr('y', y).text(text);
  }

  dragControl(context, rigth) {
    d3.event.on('drag', function () {
      const mousePoint = [d3.event.x | 0, d3.event.y | 0];
      const cells = pack.cells;

      const c = findCell(mousePoint[0], mousePoint[1]);
      if (!cells.road[c] && !d3.event.sourceEvent.shiftKey) {
        return;
      }

      context.trackCell(c, rigth);
    });
  }
}

class Planimeter extends Measurer {
  constructor(points) {
    super(points);
  }

  draw() {
    if (this.el) this.el.selectAll('*').remove();
    const size = this.getSize();

    const el = (this.el = ruler
      .append('g')
      .attr('class', 'planimeter')
      .call(d3.drag().on('start', this.drag))
      .attr('font-size', 10 * size));
    el.append('path').attr('class', 'planimeter').attr('stroke-width', size);
    el.append('text').on('click', () => rulers.remove(this.id));

    this.updateCurve();
    this.updateLabel();
    return this;
  }

  updateCurve() {
    lineGen.curve(d3.curveCatmullRomClosed.alpha(0.5));
    const path = round(lineGen(this.points));
    this.el.selectAll('path').attr('d', path);
  }

  updateLabel() {
    if (this.points.length < 3) return;

    const polygonArea = rn(Math.abs(d3.polygonArea(this.points)));
    const unit = areaUnit.value === 'square' ? ' ' + distanceUnitInput.value + '²' : ' ' + areaUnit.value;
    const area = si(polygonArea * distanceScaleInput.value ** 2) + ' ' + unit;
    const c = polylabel([this.points], 1.0);
    this.el.select('text').attr('x', c[0]).attr('y', c[1]).text(area);
  }
}

// Scale bar
function drawScaleBar(requestedScale) {
  if (scaleBar.style('display') === 'none') return; // no need to re-draw hidden element
  scaleBar.selectAll('*').remove(); // fully redraw every time
  const scaleLevel = requestedScale || scale;

  const distanceScale = distanceScaleInput.value;
  const unit = distanceUnitInput.value;
  const size = +barSizeInput.value;

  // calculate size
  const init = 100;
  let val = (init * size * distanceScale) / scaleLevel; // bar length in distance unit
  if (val > 900) val = rn(val, -3);
  // round to 1000
  else if (val > 90) val = rn(val, -2);
  // round to 100
  else if (val > 9) val = rn(val, -1);
  // round to 10
  else val = rn(val); // round to 1
  const length = (val * scaleLevel) / distanceScale; // actual length in pixels on this scale

  scaleBar
    .append('line')
    .attr('x1', 0.5)
    .attr('y1', 0)
    .attr('x2', length + size - 0.5)
    .attr('y2', 0)
    .attr('stroke-width', size)
    .attr('stroke', 'white');
  scaleBar
    .append('line')
    .attr('x1', 0)
    .attr('y1', size)
    .attr('x2', length + size)
    .attr('y2', size)
    .attr('stroke-width', size)
    .attr('stroke', '#3d3d3d');
  const dash = size + ' ' + rn(length / 5 - size, 2);
  scaleBar
    .append('line')
    .attr('x1', 0)
    .attr('y1', 0)
    .attr('x2', length + size)
    .attr('y2', 0)
    .attr('stroke-width', rn(size * 3, 2))
    .attr('stroke-dasharray', dash)
    .attr('stroke', '#3d3d3d');

  const fontSize = rn(5 * size, 1);
  scaleBar
    .selectAll('text')
    .data(d3.range(0, 6))
    .enter()
    .append('text')
    .attr('x', (d) => rn((d * length) / 5, 2))
    .attr('y', 0)
    .attr('dy', '-.5em')
    .attr('font-size', fontSize)
    .text((d) => rn((((d * length) / 5) * distanceScale) / scaleLevel) + (d < 5 ? '' : ' ' + unit));

  if (barLabel.value !== '') {
    scaleBar
      .append('text')
      .attr('x', (length + 1) / 2)
      .attr('y', 2 * size)
      .attr('dominant-baseline', 'text-before-edge')
      .attr('font-size', fontSize)
      .text(barLabel.value);
  }

  const bbox = scaleBar.node().getBBox();
  // append backbround rectangle
  scaleBar
    .insert('rect', ':first-child')
    .attr('x', -10)
    .attr('y', -20)
    .attr('width', bbox.width + 10)
    .attr('height', bbox.height + 15)
    .attr('stroke-width', size)
    .attr('stroke', 'none')
    .attr('filter', 'url(#blur5)')
    .attr('fill', barBackColor.value)
    .attr('opacity', +barBackOpacity.value);

  fitScaleBar();
}

// fit ScaleBar to canvas size
function fitScaleBar() {
  if (!scaleBar.select('rect').size() || scaleBar.style('display') === 'none') return;
  const px = isNaN(+barPosX.value) ? 0.99 : barPosX.value / 100;
  const py = isNaN(+barPosY.value) ? 0.99 : barPosY.value / 100;
  const bbox = scaleBar.select('rect').node().getBBox();
  const x = rn(svgWidth * px - bbox.width + 10),
    y = rn(svgHeight * py - bbox.height + 20);
  scaleBar.attr('transform', `translate(${x},${y})`);
}